title: Functional expression of the eotaxin receptor CCR3 in T lymphocytes co-localizing with eosinophils.
abstract: BACKGROUND
  The chemokine eotaxin is produced at sites of allergic inflammation, binds selectively to the chemokine receptor CCR3 and attracts eosinophil and basophil leukocytes, which express high numbers of this receptor. Responses of T lymphocytes to eotaxin have not been reported so far. We have investigated the expression of CCR3 in T lymphocytes and analysed the properties and in vivo distribution of T lymphocytes expressing this receptor.
  
  
  RESULTS
  In search of chemokine receptors with selective expression in T lymphocytes, we have isolated multiple complementary DNAs (cDNAs) encoding CCR3 from a human CD4+ T-cell cDNA library. T-lymphocyte clones with selectivities for protein and non-protein antigens were analysed for expression of CCR3 and production of Th1- and Th2-type cytokines. Of 13 clones with surface CCR3, nine secreted enhanced levels of interleukin-4 and/or interleukin-5, indicating that CCR3 predominates in Th2-type lymphocytes. CCR3+ T lymphocytes readily migrated in response to eotaxin, and showed the characteristic changes in cytosolic free calcium. Immunostaining of contact dermatitis, nasal polyp and ulcerative colitis tissue showed that CCR3+ T lymphocytes are recruited together with eosinophils and, as assessed by flow cytometry, a large proportion of CD3+ cells extracted from the inflamed skin tissue were CCR3+. By contrast, CCR3+ T lymphocytes were absent from tissues that lack eosinophils, as demonstrated for normal skin and rheumatoid arthritis synovium.
  
  
  CONCLUSIONS
  We show that T lymphocytes co-localizing with eosinophils at sites of allergic inflammation express CCR3, suggesting that eotaxin/CCR3 represents a novel mechanism of T-lymphocyte recruitment. These cells are essential in allergic inflammation, as mice lacking mature T lymphocytes were insensitive to allergen challenge. Surface CCR3 may mark a subset of T lymphocytes that induce eosinophil mobilization and activation through local production of Th2-type cytokines.
authors.affiliation: Theodor Kocher Institute, University of Bern, Switzerland.
authors.forename: B O
authors.initials: BO
authors.lastname: Gerber
authors.forename: M P
authors.initials: MP
authors.lastname: Zanni
authors.forename: M
authors.initials: M
authors.lastname: Uguccioni
authors.forename: M
authors.initials: M
authors.lastname: Loetscher
authors.forename: C R
authors.initials: CR
authors.lastname: Mackay
authors.forename: W J
authors.initials: WJ
authors.lastname: Pichler
authors.forename: N
authors.initials: N
authors.lastname: Yawalkar
authors.forename: M
authors.initials: M
authors.lastname: Baggiolini
authors.forename: B
authors.initials: B
authors.lastname: Moser
mesh_terms: D002465:Cell Movement / Q000276:immunology; D002999:Clone Cells; D003001:Cloning, Molecular; D003093:Colitis, Ulcerative / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D003877:Dermatitis, Contact / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D004804:Eosinophils / Q000378:metabolism* / Q000473:pathology; D015870:Gene Expression; D006801:Humans; D009298:Nasal Polyps / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D054397:Receptors, CCR3; D019707:Receptors, Chemokine / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics; D013601:T-Lymphocytes / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology
chemical_list: C515350:CCR3 protein, human; D054397:Receptors, CCR3; D019707:Receptors, Chemokine